Equine speculums have been used for over one hundred years. Early prior art speculums engaged the molars, whereas newer forms engage the incisors. One form of equine speculum used is that described in U.S. Pat. No. 5,704,901 to Meister, generally comprise U-shaped upper and lower jaw pieces extending from one side of the horses head, around past the teeth and lips to the other side of the horses head. Plates at the front of the upper and lower jaw pieces engage the incisors. The speculum is held in the mouth by means of adjustable nose and head straps, much like a bridle. A handle or lever mechanism is attached pivotally to the speculum so as to allow the user to force the lower jaw piece to rotate respective to the upper, thereby opening the horse's mouth. A single tooth pawl located on the handle, engages one of a series of teeth on the front of the lower jaw piece to maintain the open mouthed position allowing the user full access to the mouth and cheek teeth.
Other widely used variations have ratchet assemblies at the rear of the speculum, generally one on each side, used to mechanically force the jaws apart.
In the hands of capable professionals, existing dental speculums can be used with success to perform dental procedures.
Problems occur when horse owners and trainers wish to inspect the condition of their horse's teeth, either before or after dental procedures have been performed. As the cheek teeth are obscured unless the mouth is open, a speculum must be used to view them. Existing speculums are heavy and difficult to operate. In the case of the ratcheted speculum, the device must be opened first on one side and then on the other. The speculum can be opened too far, risking damage to the apparatus, but more importantly inflicting damage to the horse's jaws. Levered or ratcheted speculums present a very real danger for trapping or catching of fingers and skin within the pawls or ratchet devices. Once in place, there is a tendency for the user to put their hands inside the horse's mouth. If installed improperly, the incisors can come sideways off the plates, at the front of the speculum, and the user can be badly bitten.
An objective of the present invention is to provide a one-piece, single position speculum that can be readily inserted by those unskilled in equine dental practices, allowing the user to easily view all of the cheek teeth. Further, it is an objective to provide a speculum that does not allow the user to place their hands inside the horse's mouth while inspecting the teeth.